I had an idea that would probably render faster (if that is even an issue) but I'm not sure how much of the animation you used or have control of but....
Dunno about that, the bot flying, then 'landing' (playing the drone's portion of the animation used for entering a roboport) then minning (the repair animation of the construction robot) then taking off (exiting the roboport animation) back to flying.
having said all that, nor sure if that's less frames as I'm not sure how many frames from the player character you are using for these drones.
Man we need the return of pre-blue science construction robots.
If you want early game construction bots: https://mods.factorio.com/mod/Construction_Drones